The invention relates to a combined spark plug and fuel injection pump and more particularly it relates to a plug that is responsive directly and solely to an ignition pulse to inject fuel and provide a spark.
Certain exhaust emissions from internal combustion engines are of acute environmental concern. The emissions that are of primary concern include hydrocarbons, carbon monoxide, and nitrogen oxides. One successful approach to the reduction of such exhaust emissions is the "stratified charge" concept which has resulted in engines such as disclosed in U.S. Pat. No. 3,830,205, issued to Date and Yagi on Aug. 20, 1974. In such engines, a small volume of fuelrich mixture is supplied to a small auxiliary chamber adjacent the main combustion chamber. A spark plug is located in the small chamber and because of the richness of the fuel in the chamber, the fuel is easily ignited by the plug. A fuel-lean mixture is supplied to the main chamber which is ignited by the burning fuel in the small chamber. This arrangement results in the use of a very lean fuel mixture to the main chamber, low combustion temperatures in the main chamber, high combustion temperatures in the small chamber, long combustion times in both the small and main chamber, and complete combustion in both chambers. These conditions meet the often conflicting conditions for the reduction of hydrocarbons, carbon monoxide, and nitrogen oxides. However, the requirement for these engines of an auxiliary combustion chamber, additional valving, and additional fuel and air passages virtually precludes the retrofitting of existing internal combustion engines for stratified-charge operation. Moreover, the redesign and retooling required for existing manufactures to mass produce such engine would be a very costly and time consuming conversion.